﻿<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3c.org/TR/1999/REC-html401-19991224/loose.dtd">
<!-- saved from url=(0094)http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html -->
<HTML lang=en><HEAD><TITLE>draft: OpenID OAuth Extension</TITLE>
<META content="Wed, 07 Jan 2009 19:57:09 +0000" http-equiv=Expires>
<META content="text/html; charset=utf-8" http-equiv=Content-Type>
<META name=description content="OpenID OAuth Extension">
<META name=GENERATOR content="MSHTML 8.00.7077.0">
<STYLE type=text/css>BODY {
	BACKGROUND-COLOR: #fff; MARGIN: 2em; FONT-FAMILY: verdana, charcoal, helvetica, arial, sans-serif; COLOR: #000; FONT-SIZE: small
}
H1 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H2 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H3 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H4 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H5 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H6 {
	FONT-STYLE: normal; FONT-FAMILY: helvetica, monaco, "MS Sans Serif", arial, sans-serif; FONT-WEIGHT: bold
}
H1 {
	TEXT-ALIGN: right; BACKGROUND-COLOR: transparent; COLOR: #900
}
H3 {
	BACKGROUND-COLOR: transparent; COLOR: #333
}
TD.RFCbug {
	TEXT-ALIGN: justify; BACKGROUND-COLOR: #000; WIDTH: 30px; HEIGHT: 30px; FONT-SIZE: x-small; VERTICAL-ALIGN: middle; TEXT-DECORATION: none; PADDING-TOP: 2px
}
TD.RFCbug SPAN.RFC {
	FONT-FAMILY: monaco, charcoal, geneva, "MS Sans Serif", helvetica, verdana, sans-serif; COLOR: #666; FONT-WEIGHT: bold
}
TD.RFCbug SPAN.hotText {
	TEXT-ALIGN: center; FONT-FAMILY: charcoal, monaco, geneva, "MS Sans Serif", helvetica, verdana, sans-serif; COLOR: #fff; FONT-WEIGHT: normal
}
TABLE.TOCbug {
	WIDTH: 30px; HEIGHT: 15px
}
TD.TOCbug {
	TEXT-ALIGN: center; BACKGROUND-COLOR: #900; WIDTH: 30px; HEIGHT: 15px; COLOR: #fff
}
TD.TOCbug A {
	BACKGROUND-COLOR: transparent; FONT-FAMILY: monaco, charcoal, geneva, "MS Sans Serif", helvetica, sans-serif; COLOR: #fff; FONT-SIZE: x-small; FONT-WEIGHT: bold; TEXT-DECORATION: none
}
TD.header {
	BACKGROUND-COLOR: #666; WIDTH: 33%; FONT-FAMILY: arial, helvetica, sans-serif; COLOR: #fff; FONT-SIZE: x-small; VERTICAL-ALIGN: top
}
TD.author {
	MARGIN-LEFT: 4em; FONT-SIZE: x-small; FONT-WEIGHT: bold
}
TD.author-text {
	FONT-SIZE: x-small
}
A.info {
	Z-INDEX: 24; POSITION: relative; TEXT-DECORATION: none
}
A.info:hover {
	Z-INDEX: 25; BACKGROUND-COLOR: #900; COLOR: #fff
}
A.info SPAN {
	DISPLAY: none
}
A.info:hover SPAN.info {
	BORDER-BOTTOM: #333 1px solid; POSITION: absolute; TEXT-ALIGN: left; BORDER-LEFT: #333 1px solid; PADDING-BOTTOM: 2px; BACKGROUND-COLOR: #eee; PADDING-LEFT: 2px; WIDTH: 15em; PADDING-RIGHT: 2px; DISPLAY: block; COLOR: #900; FONT-SIZE: smaller; BORDER-TOP: #333 1px solid; TOP: 2em; BORDER-RIGHT: #333 1px solid; PADDING-TOP: 2px; LEFT: -5em
}
A {
	FONT-WEIGHT: bold
}
A:link {
	BACKGROUND-COLOR: transparent; COLOR: #900
}
A:visited {
	BACKGROUND-COLOR: transparent; COLOR: #633
}
A:active {
	BACKGROUND-COLOR: transparent; COLOR: #633
}
P {
	MARGIN-LEFT: 2em; MARGIN-RIGHT: 2em
}
P.copyright {
	FONT-SIZE: x-small
}
P.toc {
	MARGIN-LEFT: 3em; FONT-SIZE: small; FONT-WEIGHT: bold
}
TABLE.toc {
	BORDER-BOTTOM: 0px; BORDER-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px 0px 0px 3em; PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: text-top; BORDER-TOP: 0px; BORDER-RIGHT: 0px; PADDING-TOP: 0px
}
TD.toc {
	FONT-SIZE: small; VERTICAL-ALIGN: text-top; FONT-WEIGHT: bold
}
OL.text {
	MARGIN-LEFT: 2em; MARGIN-RIGHT: 2em
}
UL.text {
	MARGIN-LEFT: 2em; MARGIN-RIGHT: 2em
}
LI {
	MARGIN-LEFT: 3em
}
EM {
	FONT-STYLE: italic
}
STRONG {
	FONT-WEIGHT: bold
}
DFN {
	FONT-STYLE: normal; FONT-WEIGHT: bold
}
CITE {
	FONT-STYLE: normal; FONT-WEIGHT: normal
}
TT {
	COLOR: #036
}
TT {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE DFN {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE EM {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE CITE {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE SPAN {
	FONT-FAMILY: "Courier New", Courier, monospace; FONT-SIZE: small
}
PRE {
	TEXT-ALIGN: left; PADDING-BOTTOM: 4px; BACKGROUND-COLOR: #ccc; PADDING-LEFT: 4px; PADDING-RIGHT: 4px; COLOR: #000; PADDING-TOP: 4px
}
PRE DFN {
	COLOR: #900
}
PRE EM {
	BACKGROUND-COLOR: #ffc; COLOR: #66f; FONT-WEIGHT: normal
}
PRE .key {
	COLOR: #33c; FONT-WEIGHT: bold
}
PRE .id {
	COLOR: #900
}
PRE .str {
	BACKGROUND-COLOR: #cff; COLOR: #000
}
PRE .val {
	COLOR: #066
}
PRE .rep {
	COLOR: #909
}
PRE .oth {
	BACKGROUND-COLOR: #fcf; COLOR: #000
}
PRE .err {
	BACKGROUND-COLOR: #fcc
}
TABLE.all {
	TEXT-ALIGN: center; BORDER-RIGHT-WIDTH: 2px; BORDER-COLLAPSE: collapse; BORDER-TOP-WIDTH: 2px; BORDER-BOTTOM-WIDTH: 2px; FONT-SIZE: small; VERTICAL-ALIGN: top; BORDER-LEFT-WIDTH: 2px
}
TABLE.full {
	TEXT-ALIGN: center; BORDER-RIGHT-WIDTH: 2px; BORDER-COLLAPSE: collapse; BORDER-TOP-WIDTH: 2px; BORDER-BOTTOM-WIDTH: 2px; FONT-SIZE: small; VERTICAL-ALIGN: top; BORDER-LEFT-WIDTH: 2px
}
TABLE.headers {
	TEXT-ALIGN: center; BORDER-RIGHT-WIDTH: 2px; BORDER-COLLAPSE: collapse; BORDER-TOP-WIDTH: 2px; BORDER-BOTTOM-WIDTH: 2px; FONT-SIZE: small; VERTICAL-ALIGN: top; BORDER-LEFT-WIDTH: 2px
}
TABLE.none {
	TEXT-ALIGN: center; BORDER-RIGHT-WIDTH: 2px; BORDER-COLLAPSE: collapse; BORDER-TOP-WIDTH: 2px; BORDER-BOTTOM-WIDTH: 2px; FONT-SIZE: small; VERTICAL-ALIGN: top; BORDER-LEFT-WIDTH: 2px
}
TABLE.all {
	BORDER-BOTTOM-STYLE: solid; BORDER-BOTTOM-COLOR: black; BORDER-RIGHT-STYLE: solid; BORDER-TOP-COLOR: black; BORDER-TOP-STYLE: solid; BORDER-RIGHT-COLOR: black; BORDER-LEFT-STYLE: solid; BORDER-LEFT-COLOR: black
}
TABLE.full {
	BORDER-BOTTOM-STYLE: solid; BORDER-BOTTOM-COLOR: black; BORDER-RIGHT-STYLE: solid; BORDER-TOP-COLOR: black; BORDER-TOP-STYLE: solid; BORDER-RIGHT-COLOR: black; BORDER-LEFT-STYLE: solid; BORDER-LEFT-COLOR: black
}
TABLE.headers {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TABLE.none {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TH {
	BORDER-BOTTOM-COLOR: black; BORDER-RIGHT-WIDTH: 2px; BORDER-TOP-COLOR: black; BORDER-TOP-WIDTH: 2px; BORDER-BOTTOM-WIDTH: 3px; BORDER-RIGHT-COLOR: black; BORDER-LEFT-COLOR: black; BORDER-LEFT-WIDTH: 2px; FONT-WEIGHT: bold
}
TABLE.all TH {
	BORDER-BOTTOM-STYLE: solid; BORDER-RIGHT-STYLE: solid; BORDER-TOP-STYLE: solid; BORDER-LEFT-STYLE: solid
}
TABLE.full TH {
	BORDER-BOTTOM-STYLE: solid; BORDER-RIGHT-STYLE: solid; BORDER-TOP-STYLE: solid; BORDER-LEFT-STYLE: solid
}
TABLE.headers TH {
	BORDER-BOTTOM-STYLE: solid; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TABLE.none TH {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TABLE.all TD {
	BORDER-BOTTOM: #333 1px solid; BORDER-LEFT: #333 2px solid; BORDER-TOP: #333 1px solid; BORDER-RIGHT: #333 2px solid
}
TABLE.full TD {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TABLE.headers TD {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
TABLE.none TD {
	BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none
}
HR {
	HEIGHT: 1px
}
HR.insert {
	BORDER-BOTTOM: 0px; BORDER-LEFT: 0px; BACKGROUND-COLOR: #ccc; WIDTH: 80%; COLOR: #ccc; BORDER-TOP: 0px; BORDER-RIGHT: 0px
}
</STYLE>
</HEAD>
<BODY>
<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE>
<TABLE border=0 cellSpacing=0 summary=layout cellPadding=0 width="66%">
  <TBODY>
  <TR>
    <TD>
      <TABLE border=0 cellSpacing=1 summary=layout cellPadding=2 width="100%">
        <TBODY>
        <TR>
          <TD class=header>draft</TD>
          <TD class=header>D. Balfanz</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>B. de Medeiros</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>Google</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>D. Recordon</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>Six Apart</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>J. Smarr</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>Plaxo</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>A. Tom</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>Yahoo</TD></TR>
        <TR>
          <TD class=header>&nbsp;</TD>
          <TD class=header>January 7, 
2009</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
<H1><BR>OpenID OAuth Extension</H1>
<H3>Abstract</H3>
<P>This draft describes a mechanism to combine an OpenID authentication request 
with the approval of an OAuth request token. </P><A name=toc></A><BR>
<HR>

<H3>Table of Contents</H3>
<P class=toc><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor1">1.</A>&nbsp; 
Requirements notation<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor2">2.</A>&nbsp; 
Terminology<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor3">3.</A>&nbsp; 
Purpose of this Specification<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor4">4.</A>&nbsp; 
Overview<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#namespace">5.</A>&nbsp; 
Extension Namespace<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor5">6.</A>&nbsp; 
Discovery<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#Registered">7.</A>&nbsp; 
Before Requesting Authentication - Registration<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthReq">8.</A>&nbsp; 
Requesting Authentication<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor6">9.</A>&nbsp; 
Authorizing the OAuth Request<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthResp">10.</A>&nbsp; 
Responding to Authentication Requests<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthTokenReq">11.</A>&nbsp; 
Obtaining the Access Token<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor7">12.</A>&nbsp; 
General Considerations<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#anchor8">13.</A>&nbsp; 
Security Considerations<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#rfc.references1">14.</A>&nbsp; 
Normative References<BR><A 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#rfc.authors">§</A>&nbsp; 
Authors' Addresses<BR></P><BR clear=all><A name=anchor1></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.1></A>
<H3>1.&nbsp; Requirements notation</H3>
<P>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", 
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be 
interpreted as described in <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#RFC2119">[RFC2119]<SPAN> 
(</SPAN><SPAN class=info>Bradner, S., “Key words for use in RFCs to Indicate 
Requirement Levels,” March&nbsp;1997.</SPAN><SPAN>)</SPAN></A>. </P><A 
name=anchor2></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.2></A>
<H3>2.&nbsp; Terminology</H3>
<P>Terms <EM>emphasized</EM> are pre-defined in either the <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OpenID">[OpenID]<SPAN> 
(</SPAN><SPAN class=info>Openid.net, “OpenID Authentication 2.0 - Final,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A> or the <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OAuth">[OAuth]<SPAN> 
(</SPAN><SPAN class=info>OAuth Core Workgroup, “OAuth Core 1.0,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A> specifications. </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>Combined Consumer:</DT>
    <DD>A web service that is simultaneously an OpenID <EM>Relying Party 
    (RP)</EM> and an OAuth <EM>Consumer.</EM> </DD>
    <DT>Combined Provider:</DT>
    <DD>A web service that is simultaneously an OpenID <EM>Identity Provider 
    (OP)</EM> and an OAuth <EM>Service Provider (SP).</EM> </DD></DL></BLOCKQUOTE>
<P></P><A name=anchor3></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.3></A>
<H3>3.&nbsp; Purpose of this Specification</H3>
<P>The OpenID OAuth Extension describes how to make the OpenID Authentication 
and OAuth Core specifications work well together. In its current form, it 
addresses the use case where the OpenID Provider and OAuth Service Provider are 
the same service. To provide good user experience, it is important to present, 
to the user, a combined authentication and authorization screen for the two 
protocols. </P>
<P>This extension describes how to embed an OAuth approval request into an 
OpenID authentication request to permit combined user approval. For security 
reasons, the OAuth access token is not returned in the OpenID authentication 
response. Instead a mechanism to obtain the access token is provided. </P><A 
name=anchor4></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.4></A>
<H3>4.&nbsp; Overview</H3>
<P>Unlike standard OAuth (<A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OAuth">[OAuth]<SPAN> 
(</SPAN><SPAN class=info>OAuth Core Workgroup, “OAuth Core 1.0,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>), the OpenID OAuth Extension does 
not provision request tokens in a server-to-server request from the Combined 
Consumer to the request token endpoint at the Combined Provider. Instead, the 
Combined Provider returns an already-approved request token to the Combined 
Consumer as part of the OpenID authentication response. </P>
<P>The Combined Consumer then exchanges the request token for an access token at 
the access token endpoint of the Combined Provider, following standard OAuth 
practice. </P><A name=namespace></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.5></A>
<H3>5.&nbsp; Extension Namespace</H3>
<P>This protocol is an extension as defined by Section 12 of <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OpenID">[OpenID]<SPAN> 
(</SPAN><SPAN class=info>Openid.net, “OpenID Authentication 2.0 - Final,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>. The namespace URI for this 
extension is "http://specs.openid.net/extensions/oauth/1.0". </P>
<P>All OpenID messages that contain an OpenID OAuth Extension element MUST 
contain the following extension namespace declaration: </P>
<DIV style="WIDTH: 0px; DISPLAY: table; MARGIN-LEFT: 3em; MARGIN-RIGHT: auto"><PRE>openid.ns.&lt;alias&gt;=http://specs.openid.net/extensions/oauth/1.0</PRE></DIV>
<P>The actual extension namespace alias is determined by the party composing the 
message in such a manner as to avoid conflicts among multiple extensions. 
Throughout this document "oauth" is used as an example for the extension 
namespace alias. </P><A name=anchor5></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.6></A>
<H3>6.&nbsp; Discovery</H3>
<P>Discovery of the OpenID OAuth Extension is achieved via the mechanism 
described in <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OpenID">[OpenID]<SPAN> 
(</SPAN><SPAN class=info>Openid.net, “OpenID Authentication 2.0 - Final,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>. The OpenID OAuth Extension 
namespace "http://specs.openid.net/extensions/oauth/1.0" SHOULD be listed as an 
&lt;xrd:Type&gt; child element of the &lt;xrd:Service&gt; element in the XRDS 
discovery document. </P><A name=Registered></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.7></A>
<H3>7.&nbsp; Before Requesting Authentication - Registration</H3>
<P>The Combined Consumer and the Combined Provider agree on a consumer key and 
consumer secret (see <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OAuth">[OAuth]<SPAN> 
(</SPAN><SPAN class=info>OAuth Core Workgroup, “OAuth Core 1.0,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>). </P>
<P>The Combined Provider SHOULD in addition obtain, from the Combined Consumer, 
a list of valid OpenID realms that the Combined Consumer may use in subsequent 
authentication requests. The Combined Provider SHOULD verify that the Combined 
Consumer is authorized to use those realms. </P><A name=AuthReq></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.8></A>
<H3>8.&nbsp; Requesting Authentication</H3>
<P>When requesting OpenID Authentication via the protocol mode "checkid_setup" 
or "checkid_immediate", this extension can be used to request that the end user 
authorize an OAuth access token at the same time as an OpenID authentication. 
This is done by sending the following parameters as part of the OpenID request. 
(Note that the use of "oauth" as part of the parameter names here and in 
subsequent sections is just an example. See <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#namespace">Section&nbsp;5<SPAN> 
(</SPAN><SPAN class=info>Extension Namespace</SPAN><SPAN>)</SPAN></A> for 
details.) </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>openid.ns.oauth</DT>
    <DD>REQUIRED. Value: "http://specs.openid.net/extensions/oauth/1.0". </DD>
    <DT>openid.oauth.consumer</DT>
    <DD>REQUIRED. Value: The consumer key agreed upon in <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#Registered">Section&nbsp;7<SPAN> 
    (</SPAN><SPAN class=info>Before Requesting Authentication - 
    Registration</SPAN><SPAN>)</SPAN></A>. </DD>
    <DT>openid.oauth.scope</DT>
    <DD>OPTIONAL. Value: A string that encodes, in a way possibly specific to 
    the Combined Provider, one or more scopes for the OAuth token expected in 
    the authentication response. </DD></DL></BLOCKQUOTE>
<P></P><A name=anchor6></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.9></A>
<H3>9.&nbsp; Authorizing the OAuth Request</H3>
<P>If the OpenID OAuth Extension is present in the authentication request, the 
Combined Provider SHOULD verify that the consumer key passed in the request is 
authorized to be used for the realm passed in the request. If this verification 
succeeds, the Combined Provider SHOULD determine that delegation of access from 
a user to the Combined Consumer has been requested. </P>
<P>The Combined Provider SHOULD NOT issue an approved request token unless it 
has user consent to perform such delegation. </P><A name=AuthResp></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.10></A>
<H3>10.&nbsp; Responding to Authentication Requests</H3>
<P>If the OpenID authentication request cannot be fulfilled (either in failure 
mode "setup_needed" or "cancel" as in Sections 10.2.1 and 10.2.2 of <A 
class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OpenID">[OpenID]<SPAN> 
(</SPAN><SPAN class=info>Openid.net, “OpenID Authentication 2.0 - Final,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>) then the OAuth request SHOULD be 
considered to fail and the Provider MUST NOT send any OpenID OAuth Extension 
values in the response. </P>
<P>The remainder of this section specifies how to handle the OAuth request in 
cases when the OpenID authentication response is a positive assertion (Section 
10.1 of <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OpenID">[OpenID]<SPAN> 
(</SPAN><SPAN class=info>Openid.net, “OpenID Authentication 2.0 - Final,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>). </P>
<P>If the end user does wish to delegate access to the Combined Consumer, the 
Combined Provider MUST include and MUST sign the following parameters. </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>openid.ns.oauth</DT>
    <DD>REQUIRED. Identical value as defined in <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthReq">Section&nbsp;8<SPAN> 
    (</SPAN><SPAN class=info>Requesting Authentication</SPAN><SPAN>)</SPAN></A>. 
    </DD>
    <DT>openid.oauth.request_token</DT>
    <DD>REQUIRED. A user-approved request token. </DD>
    <DT>openid.oauth.scope</DT>
    <DD>OPTIONAL. A string that encodes, in a way possibly specific to the 
    Combined Provider, one or more scopes that the returned request token is 
    valid for. This will typically indicate a subset of the scopes requested in 
    <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthReq">Section&nbsp;8<SPAN> 
    (</SPAN><SPAN class=info>Requesting Authentication</SPAN><SPAN>)</SPAN></A>. 
    </DD></DL></BLOCKQUOTE>
<P>To note that the OAuth Authorization was declined or not valid, the Combined 
Provider SHALL only respond with the parameter "openid.ns.oauth". </P><A 
name=AuthTokenReq></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.11></A>
<H3>11.&nbsp; Obtaining the Access Token</H3>
<P>To exchange the request token for an access token, the Combined Consumer 
follows Section 6.3.1 of <A class=info 
href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#OAuth">[OAuth]<SPAN> 
(</SPAN><SPAN class=info>OAuth Core Workgroup, “OAuth Core 1.0,” 
December&nbsp;2007.</SPAN><SPAN>)</SPAN></A>, i.e., it sends an access token 
request to the access token endpoint of the Combined Provider. It SHALL use the 
following values to create the OAuth access token request: </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>consumer key</DT>
    <DD>Combined Consumers use the consumer key they established with the 
    Combined Provider in <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#Registered">Section&nbsp;7<SPAN> 
    (</SPAN><SPAN class=info>Before Requesting Authentication - 
    Registration</SPAN><SPAN>)</SPAN></A>. </DD>
    <DT>consumer secret</DT>
    <DD>Combined Consumers use the consumer secret they established with the 
    Combined Provider in <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#Registered">Section&nbsp;7<SPAN> 
    (</SPAN><SPAN class=info>Before Requesting Authentication - 
    Registration</SPAN><SPAN>)</SPAN></A>. </DD>
    <DT>OAuth token</DT>
    <DD>Combined Consumers use the request token obtained in <A class=info 
    href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#AuthResp">Section&nbsp;10<SPAN> 
    (</SPAN><SPAN class=info>Responding to Authentication 
    Requests</SPAN><SPAN>)</SPAN></A>. </DD>
    <DT>OAuth token secret</DT>
    <DD>Combined Consumers use the empty string. </DD></DL></BLOCKQUOTE>
<P></P>
<P>The Combined Provider follows Section 6.3.2 to verify the request and either 
issue the access token or send an error response. </P><A name=anchor7></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.12></A>
<H3>12.&nbsp; General Considerations</H3>
<P>The proposal takes the approach to insulate each protocol from the other, 
both for backwards compatibility as well as to enable OpenID and OAuth to evolve 
and incorporate additional features without requiring reviews of the combined 
usage described here. In particular: </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>OpenID full compatibility</DT>
    <DD>The OpenID identity provider (OP) MAY safely announce the endpoint 
    supporting the OpenID OAuth Extension to all relying parties, whether or not 
    they support the extension as well. The use of a separate service-type 
    announcement for Combined Providers endpoints provides a mechanism for 
    auto-discovery of OAuth capabilities by RPs. </DD>
    <DT>OAuth token compatibility</DT>
    <DD>The OAuth tokens approved via this mechanism MAY be used identically as 
    tokens acquired through alternative mechanisms (e.g., via standard OAuth) 
    without requiring special considerations either because of functionality or 
    security reasons. </DD></DL></BLOCKQUOTE>
<P></P><A name=anchor8></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE><A 
name=rfc.section.13></A>
<H3>13.&nbsp; Security Considerations</H3>
<P>This proposal composes protocols that provide security services 
(authentication in the case of OpenID, authorization in the case of OAuth) with 
the intention that the combined protocol provides both services simultaneously. 
Since security is not a property generally preserved by composition, the design 
takes the approach of encapsulating the OAuth flow within OpenID in a modular 
way, and applies the general rule-of-thumb of NOT introducing reliance on the 
security properties of one protocol for the correctness of the other. 
Ultimately, only public scrutiny and review can incrementally provide confidence 
that the approach described here is sound from a security perspective. </P>
<P>The following security principles are reflected in this design: </P>
<BLOCKQUOTE class=text>
  <DL>
    <DT>No long-term OAuth secrets hit the browser</DT>
    <DD>The OAuth protocol was designed so that browser-mediated communication 
    is not used to transfer long-term secrets or capabilities to access 
    data.(Instead, server-to-server calls are used to exchange such secrets). 
    Combined Providers can preserve this property by making the request_token 
    short-lived, since the request token will be exchanged for an access token 
    and secret over a server-to-server call. </DD>
    <DT>Imposters cannot retrieve the OAuth access token</DT>
    <DD>While it is possible for a malicious party to fake an OpenID request, 
    including an OpenID request that includes the OpenID OAuth Extension (the 
    request is not signed, and knowledge of the consumer key and realm is 
    sufficient to cause the Combined Provider to display an authorization page 
    for that realm/consumer), that malicious party would have to have knowledge 
    of the consumer secret to exchange the request token for an access token. 
    Note that while secure under reasonable threat models, this is different 
    from standard OAuth: In standard OAuth, one needs knowledge of both the 
    consumer key and consumer secret (or, alternatively, of a request token 
    obtained through knowledge of the consumer key and secret) to cause the 
    Service Provider to display an authorization page for that consumer. 
</DD></DL></BLOCKQUOTE>
<P></P><A name=rfc.references1></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE>
<H3>14.&nbsp;Normative References</H3>
<TABLE border=0 width="99%">
  <TBODY>
  <TR>
    <TD class=author-text vAlign=top><A name=OAuth>[OAuth]</A></TD>
    <TD class=author-text><A href="mailto:spec@oauth.net">OAuth Core 
      Workgroup</A>, “<A href="http://oauth.net/core/1.0/">OAuth Core 1.0</A>,” 
      December&nbsp;2007 (<A href="http://oauth.net/core/1.0/">HTML</A>).</TD></TR>
  <TR>
    <TD class=author-text vAlign=top><A name=OpenID>[OpenID]</A></TD>
    <TD class=author-text><A href="mailto:specs@openid.net">Openid.net</A>, 
      “<A href="http://openid.net/specs/openid-authentication-2_0.html">OpenID 
      Authentication 2.0 - Final</A>,” December&nbsp;2007 (<A 
      href="http://openid.net/specs/openid-authentication-2_0.html">HTML</A>, <A 
      href="http://openid.net/specs/openid-authentication-2_0.txt">TXT</A>).</TD></TR>
  <TR>
    <TD class=author-text vAlign=top><A name=RFC2119>[RFC2119]</A></TD>
    <TD class=author-text><A href="mailto:sob@harvard.edu">Bradner, S.</A>, 
      “<A href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to 
      Indicate Requirement Levels</A>,” BCP&nbsp;14, RFC&nbsp;2119, 
      March&nbsp;1997 (<A href="ftp://ftp.isi.edu/in-notes/rfc2119.txt">TXT</A>, 
      <A href="http://xml.resource.org/public/rfc/html/rfc2119.html">HTML</A>, 
      <A 
  href="http://xml.resource.org/public/rfc/xml/rfc2119.xml">XML</A>).</TD></TR></TBODY></TABLE><A 
name=rfc.authors></A><BR>
<HR>

<TABLE class=TOCbug cellSpacing=2 summary=layout cellPadding=0 align=right>
  <TBODY>
  <TR>
    <TD class=TOCbug><A 
      href="http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html#toc">&nbsp;TOC&nbsp;</A></TD></TR></TBODY></TABLE>
<H3>Authors' Addresses</H3>
<TABLE border=0 cellSpacing=0 cellPadding=0 width="99%">
  <TBODY>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Dirk Balfanz (editor)</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Google, Inc.</TD></TR>
  <TR>
    <TD class=author align=right>Email:&nbsp;</TD>
    <TD class=author-text><A 
      href="mailto:balfanz@google.com">balfanz@google.com</A></TD></TR>
  <TR cellpadding="3">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Breno de Medeiros (editor)</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Google, Inc.</TD></TR>
  <TR>
    <TD class=author align=right>Email:&nbsp;</TD>
    <TD class=author-text><A 
      href="mailto:breno@google.com">breno@google.com</A></TD></TR>
  <TR cellpadding="3">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>David Recordon (editor)</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Six Apart, Ltd.</TD></TR>
  <TR>
    <TD class=author align=right>Email:&nbsp;</TD>
    <TD class=author-text><A 
      href="mailto:david@sixapart.com">david@sixapart.com</A></TD></TR>
  <TR cellpadding="3">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Joseph Smarr (editor)</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Plaxo, Inc.</TD></TR>
  <TR>
    <TD class=author align=right>Email:&nbsp;</TD>
    <TD class=author-text><A 
      href="mailto:joseph@plaxo.com">joseph@plaxo.com</A></TD></TR>
  <TR cellpadding="3">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Allen Tom (editor)</TD></TR>
  <TR>
    <TD class=author-text>&nbsp;</TD>
    <TD class=author-text>Yahoo!, Inc.</TD></TR>
  <TR>
    <TD class=author align=right>Email:&nbsp;</TD>
    <TD class=author-text><A 
      href="mailto:atom@yahoo-inc.com">atom@yahoo-inc.com</A></TD></TR></TBODY></TABLE></BODY></HTML>
